FORT MYERS, Fla. – With a temper that can run hotter than one of his overpowering fastballs, Josh Beckett has never hesitated to let it be known when someone has piqued his anger.

The irascible Red Sox ace now appears to be mad at himself, saying he had “lapses in judgment” last season during Boston’s historic September collapse.

Beckett held himself accountable – for his struggles on the field and his actions in the clubhouse – Sunday as pitchers and catchers reported to spring training, while still managing to keep things on his own terms.

“I’m not saying we didn’t make mistakes, because we did make mistakes in the clubhouse,” Beckett said. “The biggest mistake I made was not pitching well against Baltimore. I was prepared to pitch every time I went out there. I just didn’t execute pitches when I needed to.”

The right-hander went 13-7 with a 2.89 ERA last year, but like the rest of the Red Sox, a sparkling first five months of the season were spoiled by a disastrous finish. He gave up 12 earned runs in his last two starts and the Red Sox went 7-20 in September to fall out of their prime position for the AL wild card.

Missing the playoffs was only the beginning. The Boston Globe then reported that some of the starting pitchers, including Beckett, Jon Lester and John Lackey, spent their off days drinking beer and eating fried chicken in the clubhouse rather than supporting their team from the dugout, painting a picture of a divided team in disarray.

“I’m upset with myself for the lapses in judgment,” Beckett said. “There’s also some ill feelings toward some people.”

He declined to specify who he was talking about, but the implication was he was upset with the anonymous sources who broke the code by speaking about what happens in the privacy of the clubhouse.

The fallout from the collapse, and the stories of clubhouse shenanigans, was immediate. Theo Epstein, the architect of two World Series-winning teams, left for the Chicago Cubs. Manager Terry Francona did not return after it became clear he lost his grip on the clubhouse in his eighth season on the job, and several changes were made to the training staff in hopes of keeping the players committed to their workout routines.

Beckett said he never missed a workout and was prepared to pitch every time he took the mound. But he did admit to adding a few pounds by the time the season ended.

“I put on a little bit of weight,” he said. “I don’t have a reason for it. But it happened. I’m looking forward to going forward from here.”

Lester also held himself accountable, saying “it’s not something I’m proud of” and vowing be a better teammate and spend more time in the dugout this season.

“I think we both know that we need to do a better job and be on the field and be around these guys more,” Lester said of himself and Beckett. “Instill in these young guys that we do work hard and we do take this seriously and that we care. That’s the biggest thing is we do care.”

Those notoriously demanding baseball fans in New England seethed all winter over the collapse, thinking those starting pitchers didn’t take enough pride in their jobs.

“I think a lot of them think that we don’t care,” Lester said. “We’re just a bunch of babies and whatever. But we do care. We want to win. And we want to get back to the playoffs and hopefully (bring a) World Series back to this town and show the fans that we are a good team.”

Beckett knows there are some fences that need to be mended back at Fenway.

“There’s some good, there’s some bad, but they’re the best fans in baseball and I think we need to earn that trust back,” Beckett said. “The way we have to do that is just go about our business the way we have in previous years and win ballgames. That’s going to be the best way.”

So much is new for the Red Sox this spring, and that’s probably a good thing as they look to put last year’s epic failure behind them.

They have a new GM in Ben Cherington, a new manager in Bobby Valentine and a shiny new spring-training facility, JetBlue Park, complete with a replica of the Green Monster in left field.

Valentine is looking to Beckett and Lester to fill the leadership void left by the departures of long-time clubhouse pillars Tim Wakefield and Jason Varitek. Wakefield announced his retirement Friday while Varitek, a beloved catcher for the last 15 years, has yet to accept a non-roster invite to spring training from Cherington.

“Whether or not a team wins a championship or comes in last, there’s always concern how the attitude will develop in a new year,” Valentine said. “Considering there were some major issues last year at the end and some major changes here in the beginning, I’m concerned about the attitude.

“But attitude filters down. When you see Josh Beckett and Jon Lester here, they’re the top of the pyramid as far as the pitchers are concerned. They came early and have been showing fantastic attitude. So far, that attitude with the pitching staff seems to be filtering down already.”